“For somehow this is tyranny's disease, to trust no friends.”

Trust? Is that a degree or level of knowledge? I think in the overall context the quote seems to be given, an accurate statement.

I get it.  We should remember that the People were never expected to 'trust' their representatives — that's why 'checks and balances' were implemented because power can corrupt. 
The Constitution, and the Bill of Rights particularly, were written to limit government power which history provides plenty of examples of abuse by 'well-meaning' rulers.  We should never trust our elected, but 'chain' them to the Constitution.